This invention relates to so-called "vocational" heavy duty trucks and trailers adapted for various off-road jobs such as concrete mixer trucks, log-hauling trucks and other trucks which carry heavy loads and are required to operate over rough and uneven ground under off-road conditions. Such trucks must also be capable of on-road highway travel.
The suspensions of the type to which the present invention relate utilize tandem axles operatively interconnected by walking beams on opposite sides of the vehicle. At their opposite ends, the walking beams are pivotally connected to the ends of the axles with the walking beams interconnected by a transverse cross tube pivotally connected to the midpoints of the walking beams. A plurality of airbags are mounted in a novel arrangement on the tops of the walking beams directly beneath fore-and-aft extending chassis frame members in supporting relationship therewith. A torque rod is connected between the rear axle and the frame to resist lateral suspension forces as the vehicle is turning. Stabilizer features are incorporated in the suspensions in accordance with the present invention so as to provide roll stability, lateral stability, and fore-and-aft (longitudinal) stability for the associated vehicles with which these suspensions are used.
In view of the foregoing, it will be seen that the object of the invention, generally stated, is the provision of new and improved tandem axle suspensions for trucks intended for off road operation over rough ground conditions which utilize walking beams which interconnect tandem axles and which incorporate structures that provide roll stability, lateral stability and fore-and-aft stability.
A further object of the invention is the provision of air ride suspensions utilizing airbags or air springs which operate at or below approximately 100 pounds per square inch pressure and which provide on-site loading capabilities.
Other objects of the invention will be obvious to those skilled in the art and will be apparent hereinafter.